1. Field of the Invention
This invention relates to a strap fastener for adjustably connecting a strap, belt or band to a variety of articles.
2. Prior Art
Various adjustable strap fasteners or buckles have been proposed which may be manipulated to adjust the effective length of a strap attached to for example a bag or a safety seat belt.
Advanced such fasteners are made of a plastic material formed into an integrally molded structure which generally comprises a pair of opposing side flanges, a grip end portion at one end of the side flanges, an anchor end portion at the opposite ends of the side flanges and a plurality of parallel cross bars disposed in between the grip and anchor end portions and extending transversely across and between the side flanges. In use, one end portion of a strap or the like is looped about one of the cross bars, passed under the anchor end of the fastener and secured in place as by riveting. The other end portion of the strap which is adapted for length adjustment is looped about another cross bar, passed under the grip end of the fastener and gripped therebetween against displacement. For ease of insertion of the strap between the cross bar and the grip end portion, the gap therebetween is desirably the larger the better. Conversely, however, the larger the gap, the tendency will be greater for the strap to get loose under tension. Vice versa, this tendency is less the smaller the gap, but the insertion of the strap becomes more difficult.
A proposition has been made whereby the gap defining surfaces are inclined progressively toward the reverse side of the fastener, instead of enlarging the insertion gap, as disclosed in Japanese Patent Laid-open (Kokai) Publication No. 54-144244. Such an attempt is however still not satisfactory in that the strap is more difficult to insert or otherwise manipulate.